That it doesn't kill the "Graendal was there"-theory, all the quotes rather indicate that truly just SH and Elza were involved - as it seems to be the case in the book - because only these two characters are mentioned regarding the scene. It seems especially unlikely that the Compulsion expert Graendal was apparently needed to find out that Elza was under Compulsion and to teach her the necessary weaves, but that Graendal wouldn't remove the Compulsion then or simply take the DM herself (after probably checking what weaves would actually be needed for Elza to open the box ). It's even said that Elza was "essential" for SH for getting things done (since SH is limited in affecting the physical world), though one wonders why SH couldn't use Graendal, if she was anyway already involved.

Ah, well, we will see.